House Natural Resources Chairman Raul M. Grijalva, D-Ariz., asked President-elect Joe Biden to block a federal land exchange for the Rio Tinto/BHP Group Resolution copper joint venture in Arizona if the Trump administration finishes a key environmental review before his inauguration.

Grijalva wrote Biden on Nov. 18 urging his transition team and any officials in his cabinet to consider rescinding the final environmental review of the project extracting minerals within a unit of land in the Tonto National Forest in Arizona known as Oak Flat. The U.S. Forest Service released a draft review in August 2019 and expects to complete the yearslong effort in December 2020, according to the agency's schedule of proposed actions for the last three months of that year.

Oak Flat is considered sacred to tribal groups including the San Carlos Apache Tribe, who wrote a letter to Biden urging him to oppose the project in August, and Grijalva asserted the Resolution project would "permanently destroy the Emory oak groves, sacred springs, and ancestral burial grounds within the area," according to letters reviewed by S&P Global Market Intelligence. "I understand that the current administration is moving forward with finalizing the EIS, and we anticipate a quick land appraisal process," the letter stated. "I urge your transition team and forthcoming Cabinet officials to consider conserving this sacred site by rescinding the EIS publication as part of your Day 1 action plan for the administration."

Dan Blondeau, senior communications adviser with Rio Tinto subsidiary Resolution Copper, confirmed to S&P Global Market Intelligence in an Nov. 19 email that the final review was expected to be completed in December. Blondeau said when the project schedule was initially set by the Forest Service in 2015, during the Obama administration, the target date for publication was July 2020. The delay was "a result of extensive public consultation, significant interagency coordination and COVID related changes to the pace of work," Blondeau said.

Representatives for the Biden transition team and BHP Group could not be immediately reached for comment.

The letter may be a preview of public opposition to the project from figures in the environmental and Native American advocacy spaces if the Trump administration does finalize the review and complete the land exchange. Ramping up production at the Resolution site could be especially lucrative to both companies as the deposit is one of the largest undeveloped copper resources in the world, according to the U.S. Forest Service. Resolution hosts resources containing 27.3 million tonnes of copper within 1.8 billion tonnes of ore grading 1.5% copper.

Rio Tinto has recently faced challenges related to its handling of mining project against the wishes of impacted Indigenous communities. The company lost some of its top executives after the company blasted a 46,000-year-old cultural heritage site in Western Australia, spurring a sharp public response that complicated mining in the region. In October, a group of 64 institutional investors worth $10.2 trillion issued a letter to the boards of 78 mining companies, including Rio Tinto and BHP Group, to improve engagement with First Nations and Indigenous communities as they obtain social licenses to operate.